Back plate assembly for mounting a heat sink assembly to a motherboard

Abstract

A back plate assembly for a motherboard includes a back plate, four posts and four plastic rings. The back plate abuts against an underside of the motherboard. The posts extend from the back plate and pass through the motherboard. The rings engage with the posts respectively and elastically abut against an upside of the motherboard.

1 . A back plate assembly for a motherboard, comprising: 
 a back plate abutting against an underside of the motherboard;    a plurality of posts extending from the back plate and passing through the motherboard; and    a plurality of elastic rings engaging around the plurality of posts respectively and elastically abutting against an upside of the motherboard.    
   
   
       2 . The back plate assembly as claimed in  claim 1 , wherein the elastic rings are open C-shaped rings and have a slight degree of deformability.  
   
   
       3 . The back plate assembly as claimed in  claim 1 , wherein the elastic rings are made of plastic material.  
   
   
       4 . The back plate assembly as claimed in  claim 1 , wherein each of posts comprises a head portion, a pole portion extending from the head portion, a neck portion extending from the pole portion and a threaded portion extending from the neck portion.  
   
   
       5 . The back plate assembly as claimed in  claim 4 , wherein the head portions of the posts abut against an underside of the back plate.  
   
   
       6 . The back plate assembly as claimed in  claim 4 , wherein the threaded portion is a hollow cylinder and defines spiral threads on an inner wall thereof.  
   
   
       7 . The back plate assembly as claimed in  claim 4 , wherein the pole portion had a diameter less than a diameter of the head portion and is engaged with the back plate.  
   
   
       8 . The back plate assembly as claimed in  claim 4 , wherein the neck portion has a diameter less than a diameter of the pole portion and less than a diameter of the threaded portion.  
   
   
       9 . The back plate assembly as claimed in  claim 8 , wherein the elastic rings surround the neck portions of the posts.  
   
   
       10 . The back plate assembly as claimed in  claim 1 , wherein the back plate comprises a cross-shaped rack and an insulated slice laid on the rack and abutting against the underside of the motherboard.  
   
   
       11 . The back plate assembly as claimed in  claim 10 , wherein the rack and the insulated slice each define through holes for the posts extending therethrough.  
   
   
       12 . A combination comprising: 
 a plurality of posts, each of the posts comprising a head portion, a pole portion extending from the head portion, a neck portion extending from the pole portion;    a plurality of rings elastically engaging with the neck portions of the posts;    a motherboard defining a plurality of apertures therein; and    a back plate attached to an underside of the motherboard and defining a plurality of through holes therein corresponding to the apertures in the motherboard;    wherein the pole portions are received in the through holes of the back plate and the motherboard, the head portions and the rings elastically sandwich the motherboard and the back plate therebetween.    
   
   
       13 . The combination as claimed in  claim 12 , wherein the head portions abut against an underside of the back plate, and wherein the rings elastically abut against an upside of the motherboard.  
   
   
       14 . The combination as claimed in  claim 12 , wherein each of the posts further comprises a threaded portion extending from the neck portion and having a diameter thereof larger than a diameter of the neck portion.  
   
   
       15 . The combination as claimed in  claim 12 , wherein the rings are open C-shaped rings and have a slight degree of deformability.  
   
   
       16 . An electronic assembly comprising: 
 a circuit board having an underside, an upside opposite the underside and a plurality of through holes through the underside and upside;    a back plate assembly having:    a rack made of metal;    an insulated slice sandwiched between the rack and the underside of the circuit board;    a plurality of posts secured to the rack and extending upwardly through the through holes in the circuit board, each post having a neck portion and a threaded portion located above the upside of the circuit board, wherein the threaded portion is located above the neck portion;    a plurality of retaining members engaging with the neck portions of the posts, respectively, and abutting against the upside of the circuit board;    a heat sink assembly mounted on the upside of the circuit board; and    a plurality of fixing components extending through the heat sink assembly to threadedly engage with the threaded portions of the posts to thereby secure the heat sink assembly to the circuit board.    
   
   
       17 . The electronic assembly as claimed in  claim 16 , wherein the retaining members are made of plastics and have a degree of elasticity and deformability, each of the retaining members having a ring-shaped configuration.  
   
   
       18 . The electronic assembly as claimed in  claim 16 , wherein the retaining members are C-shaped rings which can be expanded radially.  
   
   
       19 . The electronic assembly as claimed in  claim 18 , wherein each of the C-shaped rings has an outer diameter larger than that of the through hole of the circuit board and an inner diameter smaller than that of the neck portion before the C-shaped rings are brought to engage with the neck portions of the posts.  
   
   
       20 . The electronic assembly as claimed in  claim 16 , wherein the rack is cross-shaped having a rectangular main body and four arms extending outwardly from four corners of the main body, respectively, the posts being attached to extremities of the arms respectively.